• 대한기계학회논문집B
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• 제34권10호
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• pp.907-916
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• 2010

고온형 연료전지인 MCFC 발전시스템에 가스터빈, 유기매체 랜킨 사이클, 순산소 연소 사이클 등 다양한 하부 사이클을 추가한 통합시스템들의 성능을 비교 해석하였다. MCFC 시스템의 성능과 운전조건을 바탕으로 하여 각 추가 시스템의 주요 설계 변수 변화에 따른 통합시스템의 성능 변화를 해석하였고 이로부터 각 시스템의 최적 성능을 도출하였다. 각 시스템을 비교하여 MCFC와 최적의 결합을 나타내는 시스템을 분석하였는데, MCFC/OXY 시스템이 MCFC 단독 시스템에 비하여 가장 큰 출력 증가를 나타내었으며, MCFC/GT 시스템의 효율 증가가 가장 큰 것으로 나타났다.

• 한국수소및신에너지학회논문집
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• 제30권4호
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• pp.320-329
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• 2019

This study was performed by the numerical approach to investigate chemical behaviors of homogeneous syngas ($CO/H_2$) with nitric monoxide (NO) in pressurized oxy-fuel conditions. Hydrogen had a dominant effect to the ignition delay time of syngas due to the fast chemistry of its oxidation. Combustion was promoted by NO at the low temperature region. It was by the additional heat release through NO oxidation and production and consumption of major radicals related to the ignition. Two stage ignition behavior was shown in the pressurized condition by the accumulation of $H_2O_2$ produced from $HO_2$ radical. Additional NO oxidation was induced by the pressurized oxy-fuel condition to produce $NO_2$.

• Korean Chemical Engineering Research
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• 제47권4호
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• pp.512-517
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• 2009

순산소 연소에서 $SO_2$ 농도는 배가스의 재순환으로 인해 기존의 공기연소에 비해 3배 이상 높게 나타나고, $CO_2$ 농도와 $SO_2$ 농도가 높기 때문에 탈황현상이 기존의 공기 연소와는 다르게 나타난다. 본 연구에서는 순산소 연소조건에서 로내탈황 특성을 알아보기 위해 Drop Tube Furnace(DTF)를 이용하여, 반응온도, 유입 $SO_2$ 농도 그리고 Ca/S 비 등의 운전변수에 따른 $SO_2$ 제거효율을 측정하였으며 수분의 영향에 대해서도 알아보았다. 반응온도, 유입 $SO_2$ 농도 그리고 Ca/S 비가 증가함에 따라 $SO_2$ 제거효율은 증가하였고 유입가스 내 수분이 존재할 경우 $SO_2$ 제거효율은 약 4~6% 증가하는 것으로 나타났다.

• Korean Chemical Engineering Research
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• 제57권3호
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• pp.400-407
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• 2019

순산소 순환유동층 연소기술은 기후변화 및 연료 수급 문제들을 해결할 수 있는 기술로 주목 받고 있다. 순산소 순환유동층 연소기술은 배기가스재순환 공정을 통해 이산화탄소를 비교적 쉽게 포집할 수 있으며 대기오염물질 배출도 줄일 수 있는 친환경 연소기술이다. 새롭게 개발된 $100kW_{th}$ 급 순산소 순환유동층 연소 시스템은 연료다변화에 대응하기 위해 다양한 연료들의 순산소연소 특성을 분석하고 있으며, 본 연구에서는 높은 고정탄소 및 회분함량으로 인해 연소성이 낮은 연료로 알려진 무연탄을 활용하여 높은 이산화탄소를 생산하고 연소효율을 향상시키고자 하였다. 그 결과로서, 무연탄 순산소 연소는 아역청탄 공기연소 대비, 연소효율이 2% 향상되었으며 대기오염물질인 $SO_2$, CO, NO은 각각 15%, 60%, 99% 감소하였다. 또한, 안정적인 순산소순환유동층 연소를 통해 배기가스 내 94 vol.% 이상의 $CO_2$ 가 포집될 수 있음을 확인하였다.

• 한국연소학회지
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• 제15권2호
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• pp.1-11
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• 2010

Power generation systems based on the oxy-coal combustion with carbon dioxide capture and storage (CCS) capability are being proposed and discussed lately. Although a large number of lab scale studies for oxy-coal power plant have been made, studies of pilot scale or commercial scale power plant are not enough. Only a few demonstration projects for oxy-coal power plant are publicized recently. The proposed systems are evolving and various alternatives are to be comparatively evaluated. This paper presents a proposed approach for performance evaluation of a commercial 100 MWe class power plant, which is currently being considered for 'retrofitting' for the demonstration of the concept. The system is configurated based on design and operating conditions with proper assumptions. System components to be included in the discussion are listed. Evaluation criteria in terms of performance are summarized based on the system heat and mass balance and simple performance parameters, such as the fuel to power efficiency and brief introduction of the second law analysis. Also, gas composition is identified for additional analysis to impurities in the system including the purity of oxygen and unwanted gaseous components of nitrogen, argon and oxygen in air separation unit and $CO_2$ processing unit.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.69-74
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• 2006

An Experimental study was conducted on $CO_2$ recycle combustion heating system using pure oxygen instead of conventional air as an oxidant, which is thereby producing a flue gas of mostly $CO_2$ and water vapor($H_2O$) and resulting in higher $CO_2$ concentration. The advantages of the system are not only the ability to control high temperatures characteristic of oxygen combustion with recycling $CO_2$. but also the possibility to reduce NOx emission in the flue gas. A small scale industrial reheating furnace simulator and specially designed variable flame burner were used to characterize the $CO_2$ recycle oxy-fuel combustion, such as the variations of furnace pressure, temperature and composition in the flue gas during recycle. It was found that $CO_2$ concentration in the flue gas was about 80% without $CO_2$ recycle, but increased to $90{\sim}95%$ with $CO_2$ recycle. The furnace temperature and pressure was decreased due to recycle and the NOx emission was also reduced to maintain under 100ppm.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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• pp.43-46
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• 2012

The oxygen concentration of primary oxidizer is decided under 10% due to flammable risk. It can be a spontaneous combustion inside burner or tube if the excess oxygen is added to primary oxidizer in Oxy-PC burner. In this case, the rest oxygen which can not be injected to primary oxidizer should be injected to another port. If added it to a second oxidizer, the ignition is unstable at outlet of burner. Accordingly an extra lancing port is needed to insert into the burner unlike other common air mode. And the flame formation and combustion characteristic differ from lancing port position. Therefore we observed flame formation which has stable combustion characteristic according to the shape and position of lancing port.

• 한국대기환경학회지
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• 제33권5호
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• pp.473-479
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• 2017

This study was designed to understand characteristics of oxy-combustion of coal, dried sewage sludge and solid refuse fuel (SRF). Thermogravimetric analysis was conducted by burning the fuels with air, 21% oxygen ($O_2$)/79% carbon dioxide ($CO_2$) and 30% $O_2/70%$ $CO_2$. Heating rates were varied as 5, 10, 25, 40 and $100^{\circ}C/min$. Complete coal combustion was found at the heating rates of 5, 10, 25 and $40^{\circ}C/min$, and different combustion behavior was found with the gas composition at the heating rates of 10, 25, 40 and $100^{\circ}C/min$. Coal combustion with 30% $O_2/70%$ $CO_2$ showed the highest while coal combustion with 21% $O_2/79%$ $CO_2$ showed the lowest combustion rate. On the other hand, the combustion of dried sewage sludge and SRF showed similar combustion behavior with respect to the combustion gas composition. This suggests that oxy-combustion of dried sewage sludge and SRF which contain a large amount of volatile matter may show similar combustion behavior to their air combustion.

• 대한기계학회논문집B
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• 제33권1호
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• pp.38-45
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• 2009

Oxy-fuel combustion of pulverized coal is one of the promising new technologies to reduce $CO_2$ and NOx from coal combustion. However, the stability of pulverized coal flame is reduced in the oxy-fuel combustion. This flame stability is concerned with the flame propagation that is affected by surrounding gas and coal characteristics, such as gas temperature, gas composition, coal volatile, coal activation energy and coal size. In this paper, a study on the influence of surrounding gas and coal characteristics on the flame propagation velocity in oxy-fuel combustion of pulverized coal was preformed. One dimensional model was used to calculate the flame propagation velocity of pulverized coal clouds. In this model, the radiation is considered to be the main source of heat exchange, and Monte Carlo method was adopted for accurate calculation of radiation heat flux. It was found that the flame propagation velocity become higher with the decrease of coal activation energy and the increase of coal volatile. Also, according to the increase of gas temperature and $O_2$ concentration, flame propagation velocity increased.

• 한국연소학회지
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• 제15권2호
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• pp.34-40
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• 2010

The effect of co-firing with pulverized coal and wood biomass on ignition and burn-out temperature was investigated at air and oxy-fuel conditions by thermo gravimetric analyzer(TGA). Three kinds of coal(shenhua, adaro, wira) were selected and mixing ratios of coal and wood biomass was set to 1, 0.5, and 0.8. The ignition temperature depended on the amount of volatile matter of blended fuel, while the burn-out temperature was dominated by the oxidant ingredients. The oxy-fuel condition with an oxygen ratio(Ofr,o) of 0.3 showed similar tendency with air condition in the heat flow measurement. Volatile matter reaction, however, became dominant when oxygen ratio exceeded 0.8 for co-firing combustion of wood biomass and pulverized coal.